Apparatus and methods for accelerating dental treatments

ABSTRACT

Apparatus, kits and methods for providing accelerated treatment of a patient&#39;s teeth. The apparatus, kits and methods involve the use of a dental impression tray that includes a patient dentition impression formed from a dental impression material such as an alginate. The impression tray advantageously includes heating means for heating and maintaining the formed patient dentition impression at a temperature greater than about 105° F. The heated dental trays may be used to accelerate the activity of dental bleaching agents (e.g., peroxides), desensitizing agents (e.g., potassium nitrate), remineralizing agents (e.g., fluoride salts), and the like. A dental office procedure for treating teeth involves the basic steps of (1) coating a specially-prepared patient dentition impression with a dental composition such as a bleaching, desensitizing or remineralizing composition; (2) placing the coated patient dentition impression into the patient&#39;s mouth; (3) heating the patient dentition impression and dental composition to a temperature of at least about 105° F.; and (4) retaining the patient dentition impression in position for period of time in a range of about 1 minute to about 60 minutes. The procedure can be adapted to microwave heating, electrical resistance heating, or hot fluid heating of the patient dentition impression.

RELATED APPLICATION

[0001] This application is a continuation-in-part of copending U.S.application Ser. No. 09/565,752, filed May 8, 2000. For purposes ofdisclosure, the foregoing application is incorporated herein by specificreference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention is in the field of apparatus and methods for usein accelerating the activity of dental bleaching compositions. Moreparticularly, the invention is in the field of apparatus and methods foraccelerating the activity of e.g., dental bleaching, desensitizing andremineralizing compositions by means of a heated dental impressionmaterial.

[0004] 2. Review of the Relevant Technology

[0005] In the last decade there has been a proliferation of compositionsand methods for bleaching teeth. Compositions for both in-office orat-home use typically include a peroxide bleaching agent, such ascarbamide peroxide, hydrogen peroxide or sodium perborate. Carbamideperoxide is a complex of urea and hydrogen peroxide. Sodium perborate isa complex of sodium borate and hydrogen peroxide. On the other hand,hydrogen peroxide by itself only exists in aqueous form and is generallyunstable except at relatively low pH.

[0006] When formulating an appropriate bleaching composition there isinherently a tradeoff between stability and reactivity. It is desirablefor a bleaching composition to remain stable between the time when it ismanufactured and when it is used to bleach a person's teeth. However,once placed on a person's teeth it is desirable for the composition toquickly break down and release active oxygen radicals capable ofbleaching teeth. In general, compositions that are sufficiently stableso as to have good shelf life tend to bleach teeth slowly over time,typically over a period of weeks with daily regimens of from one toeight hours. On the other hand, bleaching compositions that are capableof bleaching teeth in shorter periods of time generally do not have along shelf life and are typically prepared just prior to application toa person's teeth.

[0007] There are at least two known ways of triggering accelerateddecomposition of active oxygen radicals from peroxide-containingbleaching compositions. One way is through the use of chemicals orcatalysts that are known to destabilize peroxides. Such agents aretypically mixed in with the peroxide bleaching agent just prior toapplication to the person's teeth.

[0008] Another way to accelerate the bleaching activity ofperoxide-based bleaching compositions is through the application ofheat. Examples of apparatus used to generate heat include conventionaldental curing lamps used to cure composites and lasers. A draw-back thatis common to both curing lamps and lasers is that it is typically notpossible to simultaneously heat all of a patient's teeth, thusincreasing the time it takes to complete the bleaching process as wellas leading to the possibility of unequal application of heat to thevarious teeth. Another drawback to the use of a curing lamp,particularly one that is able to focus light or heat energy to an areathat is greater than the size of the labial surface of a tooth to bebleached, is that the curing lamp tends to be indiscriminate as towhether it heats the tooth or surrounding gingival tissue, thuspotentially causing discomfort to the patient. Accordingly, it istypically necessary to protect the patient's gingival tissue through theuse of a protective rubber dam coating material.

[0009] In the case of at-home bleaching regimens, a customized patientbleaching tray or mouth guard is typically formed using a multi-stepprocedure. This procedure typically includes the steps of (1) makingconventional alginate impressions of the patient's maxillary and/ormandibular teeth, (2) preparing stone cast models of the patient's upperand lower teeth from the alginate impressions using plaster of paris,followed by trimming away of the excess plaster, (3) blocking out on thetrimmed cast stone models, using a conventional light-cured orlight-activated, acrylic-based resin laboratory block-out gel, thosetooth areas to be whitened so as to form reservoirs in the resultingtray, (4) vacuum forming a 5-inch by 5-inch sheet of 0.040-inch to0.080-inch thickness clear plastic resin mouth guard material over eachstone cast model, (5) removing the tray from the model, and (6) suitablytrimming the tray so that it doesn't overlap the gingival margin. Insome cases the tray is “scalloped” by trimming up and around the dentalpapilla. The dental tray is then ready for delivery to the patient aspart of the home-use whitening kit. Home-use bleaching regimensemploying the custom dental tray and whitening composition (e.g., acarbamide peroxide gel) typically involves a series of 1 to 8 hourbleaching treatments repeated daily over a period of about 2 to 6 weeksdepending upon the degree or severity of dentition staining.

[0010] In view of the foregoing, there has been a long felt need in theart to provide apparatus and methods for use in accelerating thebleaching activity of conventional bleaching compositions in a mannerthat is both more comfortable from the point of view of the patient andmore economical in terms of cost and time. It would be particularlyuseful of such apparatus were disposable, that is, of sufficiently lowcost and simplicity of design so that it could be used for a singlepatient and then disposed of.

[0011] It would be further advancement in the art if the foregoingapparatus and methods could be used to accelerate the activity of otherdental compositions, e.g., desensitizing and/or remineralizing compoundsthat include potassium nitrate and/or fluoride salts.

[0012] Such apparatus and methods for increasing the activity ofbleaching, desensitizing and remineralizing or other dental compositionsare disclosed and claimed herein.

SUMMARY AND OBJECTS OF THE INVENTION

[0013] The present invention relates to apparatus and methods used toaccelerate the activity of dental compositions by means of theapplication of heat. In particular, the invention relates to apparatusand methods for treating teeth that involve conventional or speciallyadapted dental impression trays in conjunction with a heated impressionmaterial. The use of impression material provides the dentist with theability to manufacture what is, in essence, a customized tray that canbe immediately used to treat a patient's teeth using a variety of dentalcompositions, (e.g., dental bleaching, desensitizing, or remineralizingcompositions). The formed impression material can be heated by, e.g.,microwave energy, resistive heating devices, or a heated fluid in orderto accelerate the rate at which the dental composition is able to carryout its intended treatment of a patient's teeth.

[0014] The apparatus according to the present invention mayadvantageously be sold or provided to a dentist in the form of one ormore kits that include at least a portion of the means necessary to formand then heat a dentition impression of the patient's teeth, followed bytreatment of a patient's teeth using an appropriate dental composition.Such kits will preferably include, at a minimum, a dental impressiontray capable of receiving sufficient impression material so as to makean impression of at least a portion of the patient's teeth, means forheating the impression during the treatment process, and one or moredental compositions, such as compositions that include at least one of adental bleaching agent (e.g., a peroxide bleaching agent), adesensitizing agent (e.g., a potassium salt such as potassium nitrate),or a remineralizing agent (e.g., a fluoride salt such as sodiumfluoride). The kits may optionally include an impression material, suchas a standard alginate impression material known in the art.Nevertheless, because most dentists already have standard impressionmaterials on site for other purposes, it is typically not necessary forthe kits to include such impression materials.

[0015] A preferred embodiment of utilizing the apparatus disclosedherein to carry out accelerated treatment of a patient's teeth includesthe following steps: (1) filling at least a portion of a dentalimpression tray with an unset dental impression material; (2) placingthe filled dental impression tray into the patient's mouth in order totake an impression of at least a portion of the patient's teeth; (3)maintaining the impression tray in place for a sufficient length of timefor the dental impression material to at least partially cure to therebyform a patient dentition impression; (4) removing the dental impressiontray and included formed patient dentition impression from the patient'smouth; (5) placing an appropriate quantity of a dental compositionwithin the formed patient dentition impression; (6) introducing thedental impression tray and included formed patient dentition impressionwith the dental composition into the patient's mouth so as to at leastapproximately register the patient's teeth and the corresponding formedpatient dentition impression; (7) heating and/or maintaining thetemperature of the formed patient dentition impression at a temperatureof at least about 105° F.; and (8) removing the dental impression tryand included dentition impression from the patient's mouth andthoroughly rinsing the patient's mouth prior to release of the patient.

[0016] In a preferred embodiment, the formed patient dentitionimpression will be heated to and maintained at the desired temperatureby means of an electrical resistance heating element located within, orotherwise associated with, the dental impression tray. The dentitionimpression may alternatively be heated by means of microwave energy orby the use of a heated fluid. The temperature of the dentitionimpression is preferably maintained in a range of about 110° F. to about150° F., more preferably in a range of about 120° F. to about 140° F.

[0017] In the case where an electrical resistance heating element isused, the dental impression tray will be electronically connected to apower supply, such as a DC power supply that supplies a desired amountof power. In a preferred embodiment, the patient may be given a controldevice that interacts with the power supply so as to heat and maintainthe dentition impression at an elevated, yet comfortable, temperature soas to optimize patient comfort and dental composition activity. In orderto further maximize patient comfort, it may be advantageous to trim awaya portion of the patient dentition impression that would otherwisecontact or overlap the patient's gingival tissue. In this way the heatcan be concentrated or focused on the teeth and kept away from the muchmore sensitive gingival tissue surrounding the teeth.

[0018] The treatment times according to the present invention typicallyrange of about 1 minute to about 60 minutes, more preferably in a rangeof about 5 minutes to about 30 minutes, depending on the dentalcomposition being used, as well as the time necessary for carrying out adesired treatment. Where it has heretofore been known that heat is ableto destabilize peroxide-based dental bleaching agents so as toaccelerate the liberation of oxygen radicals used in bleaching teeth, ithas heretofore not been known that heat can also accelerate thebeneficial effects of other dental agents, such as desensitizing agentsbased on potassium nitrate or remineralizing agents based on fluoridesalts. This is a surprising result since neither potassium nitrate norfluoride salts decompose when heated to the temperatures describedherein.

[0019] Accordingly, it is an object of the invention to provideapparatus and methods for use in accelerating the bleaching activity ofconventional bleaching compositions in a manner that is both morecomfortable from the point of view of the patient and economical interms of cost and time.

[0020] It is a further object to provide apparatus that is disposableand that is of sufficiently low cost and simplicity of design so that itcan be used for a single patient and then disposed of.

[0021] It is a further object of the invention to provide apparatus andmethods that can be used to accelerate the activity of other dentalcompositions, such as desensitizing and/or remineralizing compounds thatinclude potassium nitrate and/or fluoride salt.

[0022] These and other objects and features of the present inventionwill become more fully apparent from the following description andappended claims, or may be learned by the practice of the invention asset forth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order that the manner in which the above-recited and otheradvantages and objects of the invention are obtained, a more particulardescription of the invention briefly described above will be rendered byreference to a specific embodiment thereof which is illustrated in theappended drawings. Understanding that these drawings depict only atypical embodiment of the invention and are not therefore to beconsidered to be limiting of its scope, the invention will be describedand explained with additional specificity and detail through the use ofthe accompanying drawings in which:

[0024]FIG. 1 depicts a preliminary procedural step of coating theprincipal cavity of an alginate dental impression tray with aconventional adhesive;

[0025]FIG. 2 depicts a preliminary step of applying a dental wax overlayto the surfaces of the patient's teeth that are to be whitened;

[0026]FIG. 3 illustrates the step of placing an unset conventionaldental impression material in the principal cavity of the dentalimpression tray of FIG. 1;

[0027]FIG. 4 is a cross-section view taken at line 4-4 of FIG. 3 andextending transversely through the filled dental impression tray of FIG.3;

[0028]FIG. 5 depicts the act of inserting the compound-filled dentalimpression tray of FIGS. 3 and 4 into a patient's mouth forimpression-setting purposes;

[0029]FIG. 6 is a plan view of the completed dental impression prior towax overlay removal;

[0030]FIG. 7 is a cross-section view taken at line 7-7 of FIG. 6;

[0031]FIG. 8 is a cross-section view similar to FIG. 7 but afteraccomplishing wax overlay removal;

[0032]FIG. 9 is a cross-section view taken at line 9-9 of FIG. 6;

[0033]FIG. 10 is a cross-section view taken at line 9-9 of FIG. 8 butwith an alternative dental impression material having a particulatefiller dispersed therein;

[0034]FIG. 11 depicts the step of placing a dental composition into theformed dental impression cavity preparatory to treating the patient'steeth;

[0035]FIG. 12 depicts the placement of the tray of FIG. 11 into thepatient's mouth in order to effect bleaching;

[0036]FIG. 13 schematically depicts an alternate embodiment of a dentalimpression material and impression tray in which resistive heat isemployed to heat and maintain the proper temperature of the set dentalimpression material;

[0037]FIG. 14 is a cross-section view taken at line 14-14 of FIG. 13;

[0038]FIG. 15 schematically depicts another alternative embodiment of adental impression material and impression tray in which a heated fluidis used to heat and maintain the proper temperature of the set dentalimpression material;

[0039]FIG. 16 is a cross-section view taken at line 16-6 of FIG. 15;

[0040]FIG. 17 is a perspective view of an alternative dental impressiontray equipped with resistive heating elements;

[0041]FIG. 18 is a perspective view of the dental impression tray ofFIG. 17 into which a dental impression material has been placed into theupper half of the impression tray.

[0042]FIG. 19 is a cross-section view taken at line 19-19 of FIG. 18;

[0043]FIG. 20 is a perspective view of a heating element used in adental impression tray according to the invention; and

[0044]FIG. 21 schematically depicts an integrated system employing theimpression tray of FIG. 17 together with a power supply and acontroller.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0045] I. Introduction.

[0046] The present invention encompasses apparatus and methods foraccelerated treatment of a patient's teeth, typically in an in-officeprocedure, utilizing a conventional or specially adapted dentalimpression tray in conjunction with a heated dental impression material.Examples of dental compositions that have been found to provideaccelerated treatment when heated include bleaching, desensitization andremineralizing compositions. The impression material may be heated,e.g., by means of microwave energy, a resistive heating device, or aheated fluid so as to accelerate the rate at which the dentalcomposition acts on the patient's teeth. Other optional steps may beperformed, as desired.

[0047] The use of an impression material to make what is in essence acustomized dental tray into which an appropriate dental composition canbe loaded eliminates the time-consuming practice of manufacturing acustomized dental tray. Moreover, the heated impression materials of thepresent invention are far less expensive than expensive lasers, or evenrelatively inexpensive curing lamps, but provide similar or evensuperior results. Because dental impression trays and impressionmaterials are so inexpensive, they may be used once and then discarded.

[0048] II. Apparatus for Forming and Heating a Patient DentitionImpression.

[0049] The basic component of the apparatus and systems according to theinvention is the dental impressing tray. One of the purposes of thedental impression tray is receive and retain a dental impressionmaterial during the formation of a patient dentition impression and alsoduring subsequent treatment of the patient's teeth. The impression traywill advantageously include means for heating the formed patientdentition impression during the treatment process. Nevertheless,virtually any dental impression tray, both conventional or specialized,may be used within the scope of the present invention, in combinationwith an impression material, to form a dentition impression of apatient's teeth to be treated.

[0050] Examples of suitable dental trays that include means for heatinga formed dentition impression are illustrated more particularly in FIGS.13-21. More preferred are dental impression trays that incorporate, orotherwise have associated therewith, a resistive heating element, suchas the trays illustrated in FIGS. 13-14 and 17-21, which shall bediscussed first.

[0051]FIGS. 13 and 14 illustrate a dental impression tray 10 accordingto the present invention that includes a resistive heating element orwire. Impression tray 10 includes one or more heating wires 34 that arelooped around within an interior cavity 12 of the tray 10 prior tofilling tray cavity 12 with an unset or uncured dental impressionmaterial 16. During use, the one or more heating wires 34 are connectedto a power supply 32. Together, the impression tray 10 and power supply32 form a system 30 that is capable of heating the impression material16 disposed within the interior trough of the tray 10. Because theimpression tray 10 is advantageously disposable, or at least in order toseparately store the tray 10 and power supply 32, the one or moreheating wires 34 are advantageously coupled to the power supply 30 bymeans of conventional or specialized electrical connectors 36.

[0052] Although FIG. 14 depicts an arrangement wherein the heating wires34 are embedded within the impression material 16, any arrangementwhereby impression tray 10 is able to heat and maintain the impressionmaterial 16 within a desired temperature range is within the scope ofthe invention. In an experimental embodiment of apparatus 30,approximately 40 to 50 inches of No. 24 insulated audio speaker wirewere used as resistance heating wire 34. Power supply 32 comprised aconventional 120/30 volt alternating current step-down transformer witha 2.5 ampere output current, an alternating current-to-direct currentrectifier, an electronic intermittent switch having 30-40 second ontimes alternated with 30-40 second off times, and a system on-off timerswitch mechanism. The power supply timer functioned to activate powersupply 32 for periods of time in a range of from 1 to 15 minutes.

[0053] FIGS. 17-21 depicts an alternative dental impression tray 50configured so as to be able to treat the upper and lower teeth of apatient of the same time. As shown in FIG. 17, dental impression tray 50includes a generally arcuate structure 52, which defines an interiorregion for receipt of a dental impression material 64 (FIG. 18). Arcuatestructure 52 is attached to a handle 62, which serves the dual purposeof facilitating gripping by the dental practitioner as well as providinga protective housing for wires 60 used to supply an electric currentused to heat a formed dentition impression of the patient's teeth (notshown) within dental impression tray 50.

[0054] Tray 50 further includes a substantially planar divider orbarrier 54, which provides opposing surfaces for placement of animpression material 64 on either side of divider 54. Divider 54 maycomprise any appropriate material, examples of which include a solidmetal or plastic sheet, or a wire or nylon fabric or mesh. A generallycurved wall 56 assists in retaining the alginate or other impressionmaterial within the space between arcuate structure 52 and wall 56. FIG.17 further depicts a pair of heating elements 58 a and 58 b disposed onan interior surface of arcuate structure 52, which are used to heat animpression material.

[0055]FIG. 18 depicts tray 50 into which an unset impression material 64has been placed within the space defined by wall 56 and arcuatestructure 52 on an upper surface of divider 54. In the case where itwill be desired to bleach both the upper and lower teeth, a layer ofimpression material 64 may also be placed on the underside of divider54. The use of a mesh or other porous material as the divider 54promotes adhesion of the impression material 64 onto the surface of thedivider 54, even on the underside. Of course, glue or other adhesionaids may be used as desired to retain the impression material 64 withinthe tray 50.

[0056] It will be appreciated that a person's gums or gingiva aretypically more sensitive to heat than teeth. Accordingly, it may bedesirable to trim back a portion of the cured impression material of theformed patient dentition impression in the area of the gingivalinterface. In this way the cured impression material advantageouslytouches or is adjacent to only the patient's teeth being treated ratherthan the more sensitive gingival tissue.

[0057] In order to heat the formed patient dentition during treatment,heating elements 58 a and 58 b heat up as an electrical current ispassed therethrough. As more particularly shown in FIG. 19, wires 60deliver an appropriate electrical current to heating elements 58 a and58 b. In the case where the heating elements 58 a and 58 b are relied onto generate heat, they should comprise an appropriate high resistancemetal or other poorly conductive material capable of generating heatwhen a current is passed therethrough.

[0058] In the alternative, heating elements 58 a and 58 b may passivelyact as heat sinks that assist in distributing heat generated by adjacentheating element wires in contact with elements 58 a and 58 b. In thisway, elements 58 a and 58 b may not themselves generate heat but willact to better disperse heat over a wider area compared to heatingelement wires in contact with heating elements 58 a and 58 b. In such acase, the heating elements 58 a and 58 b may advantageously comprise ametal or other material that readily conducts heat, such as aluminum.

[0059] As more fully depicted in FIG. 20, heating element 58 includes achannel 59 into which one or more electrical wires 60 are placed so asto deliver an appropriate current to the heating element 58 in order tocause heating element 58 to generate heat. In the alternative, the oneor more wires 60 may include a length of a heating wire, such as aNi-Cad wire, disposed within channel 59. In this embodiment, the Ni-Cadwire, rather than the metallic heating element 58, will be primarilyresponsible for generating the heat used to heat up the patientdentition impression (not shown) formed from the impression material 64in order to accelerate activity of the dental agent. In this case,metallic heating element 58 will act primarily as a heat sink used totransfer heat energy from the Ni-Cad wire to the impression material 64.

[0060] It should be understood that any appropriate power supply may beused so long as it is able to provide a desired quantity of electricalenergy in order to heat the impression material to within a desiredtemperature range. As shown in FIG. 21, a preferred system 70 accordingto the invention includes a dental impression tray 50 as described inFIGS. 17-19, together with a power supply 72 and a controller 74. In oneembodiment, the power supply will provide between 5 and 10 volts of DCcurrent at 1.2 amperes to each of heating elements 58 a and 58 b. Thecontroller 74 may be operated by either the patient or the dentalpractitioner as desired. Allowing the patient to control the temperatureof the dental tray and associated patient dentition within the patient'smouth will allow for optimization between patient comfort and treatmenttime. The optimum temperature may vary from patient to patient dependingon how sensitive a patient is to heat. In general, the optimumtemperature in terms of minimizing treatment time, while being sensitiveto patient comfort, will be the maximum temperature at which the patientstill feels comfortable and is not experiencing excessive pain ordiscomfort.

[0061] In a preferred embodiment, the temperature within the impressionmaterial may be measured by means of a diode (not shown), which is anextremely inexpensive device for measuring temperature but which ispreferred where impression tray 50 is intended to be disposable. Whilediodes are not necessarily as accurate as other devices for measuringtemperature, such as thermocouples, they have adequate accuracy withinthe narrow temperature ranges involved in the present invention (e.g.,preferably about 110-150° F., more preferably about 120-140° F.).

[0062]FIGS. 15 and 16 depict an alternative system 40 for continuouslyheating a patient dentition impression tray 10 during a desired dentaltreatment regimen. System 40 includes a hot fluid supply 42 in fluidcommunication with a looped tubular fluid conduit 44 disposed within theprincipal cavity 12 of the impression tray 10. The fluid conduit 44 maybe selectively connected to and disconnected from the hot fluid supply42 by means of conventional fluid connectors 46. In this embodiment, thedental impression tray 10 is provided with the looped fluid conduit 44disposed in the bottom of principal cavity 12 prior to filling thecavity 12 with unset or uncured dental impression material 16. In anexperimental embodiment of apparatus 40, {fraction (1/8)} inch rigidplastic fluid conduit was used as fluid conduit 44 connected to a supply42 of water heated to approximately 130° F. Satisfactory results wereobtained where the apparatus was retained in a patient's mouth for aperiod of time in a range of about 5 minutes to about 20 minutes.

[0063] The afore-mentioned resistive heating elements or wires and theheated fluid constitute different examples of heating means for heatinga formed patient dentition impression. Another example of a resistiveheating device is an etched resistive circuit. For purposes of thisdisclosure and the appended claims, the term “heating means” generallyincludes any heating apparatus known in the art that is or can beadapted for use with a dental impression tray to heat a formed patientdentition impression. Moreover, the term “fluid” shall be understood tobroadly include substances in a gaseous, liquid or supercritical fluidstate.

[0064] Other dental impression trays may alternatively be used inconnection with the present invention, including those illustrated inFIGS. 1-12. FIGS. 1-12 depict one possible method sequence using aconventional dental impression tray 10 that includes a principal cavity12. Even though FIGS. 1-12 depict a method of using a conventionaldental impression tray 10, the general method steps illustrated thereinmay be generalized as having applicability to methods that employ thedental trays depicted in FIGS. 13-21, keeping in mind that some of thesteps depicted in FIGS. 1-12 are merely optional. While certainly withinthe scope of the invention, the use of a conventional dental impressiontray that is not adapted with heat generating means will typicallyrequire the use of an external heat source, such as a heater ormicrowave capable of temporarily imparting heat energy to the dentaltray and/or included patient dentition impression.

[0065] III. Methods of Treatment.

[0066] In general, any method that employs the use of a heated patientdentition impression in order to accelerate the treatment of a patient'steeth using a dental composition is within the scope of the invention.The term “dentition impression” should be broadly interpreted to includeany depression or void space formed within an impression materialregardless of whether or not the depression closely or only very roughlyapproximates the patient's teeth. Preformed, non-custom depressions orvoid spaces formed within an impression material are within the scope ofthe term “dentition impression”.

[0067] It has been found that heating and maintaining dentalcompositions such as dental bleaching, desensitizing or remineralizingcompositions at elevated temperatures using a heated dentitionimpression greatly reduces the treatment time. In some cases (e.g., indental bleaching), the heat causes more rapid decomposition of theactive ingredient. In other cases (e.g., in desensitizing orremineralizing), the heat does not cause the active ingredient todecompose but nevertheless increases the rate by which the activeingredient interacts with a person's teeth in order for the activeingredient to impart its beneficial properties. The use of a heateddentition impression greatly reduces the time and hassle, and increasespatient comfort, compared to treatments that utilize conventional heatsources, such as lasers or dental curing lamps.

[0068] In an exemplary method for utilizing the apparatus disclosedherein in order to carry out accelerated treatment of a patient's teeth,the following steps are employed: (1) filling at least a portion of adental impression tray with a dental impression material, preferably anunset dental impression material; (2) placing the filled dentalimpression tray into the patient's mouth in order to take an impressionof at least a portion of the patient's teeth; (3) maintaining theimpression tray in place for a sufficient length of time for the dentalimpression material to at least partially cure to thereby form a patientdentition impression; (4) removing the dental impression tray andincluded formed patient dentition impression from the patient's mouth;(5) placing an appropriate quantity of a dental composition within theformed patient dentition impression; (6) introducing the dentalimpression tray including the formed patient dentition impression anddental composition into the patient's mouth so as to at leastapproximately register the patient's teeth with the formed patientdentition impression; (7) heating and/or maintaining the temperature ofthe formed patient dentition impression at a temperature of at leastabout 105° F. (preferably in a range of about 110° F. to about 150° F.,more preferably in a range of about 120° F. to about 140° F.); and (8)removing the dental impression try and included dentition impressionfrom the patient's mouth and thoroughly rinsing the patient's mouth.

[0069] In order to illustrate one exemplary method for treating apatient's teeth according to the invention, reference is now made toFIGS. 1-12. FIG. 1 depicts an optional preliminary step of brushing orotherwise applying a dental impression adhesive onto the surface of theprincipal cavity 12 of a conventional, disposable alginate dentalimpression tray 10. In one embodiment, one such tray 10 is required forthe mandibular (or lower) teeth that are to be whitened, and a separatebut like tray 10 may be used for treating the patient's maxillary (orupper) teeth. It will be appreciated, however, that it is within thescope of the invention to utilize a two-sided impression tray capable ofreceiving impression material sufficient for both the top and bottomteeth.

[0070]FIG. 2 depicts an optional step of applying a sheet-like dentalwax overlay 14 onto those surfaces of the patient's teeth that are to bewhitened—usually just to the facial aspects of the teeth. The purpose ofthe wax sheet is to create more space between the formed dentalimpression and the patient's teeth so as to hold an additional quantityof dental composition, if desired. It should be understood, however,that treatment of the patient's teeth is possible with or without thisextra space formed as a result of the wax overlay 14. Other blockoutmaterials may be used, such as curable liquids, coatings or pliablematerials, collectively referred to as “amorphous blockout materials”.

[0071]FIG. 3 depicts the step of filling the principal cavity 12 of animpression tray 10 with a suitable quantity of an impression material16, typically an unset alginate dental impression material or catalyzeddental impression compound. FIG. 4 is a cross-sectional view of a tray10 according to FIG. 3 that has been filled with impression material 16prior to insertion of the tray 10 into the patient's mouth.

[0072]FIG. 5 depicts the step of inserting the impression tray 10 andimpression material 16 into a patient's mouth. Thereafter, the patientis asked to gently bite down into the impression material 16 so as toconform the impression material 16 to the shape of the patient's teethand thereby form a patient dentition impression 18 (see FIG. 6). In apreferred embodiment, the impression material 16 will comprise a curableimpression material, and the tray 10 will be held in place within thepatient's mouth for a sufficient length of time for the dentalimpression material 16 to at least partially set or cure in order toyield a formed dentition impression 18 that will maintain its shape whenremoved from the patient's mouth.

[0073] Following removal of dental impression tray 10 with its includedformed patient dental impression 18 from within the patient's mouth, anywax overlay or other blockout material 14 that is retained on thesurfaces of patient dentition impression 18 is manually removed from theimpression 18 by appropriate manual scraping or the like. In addition,some of the impression material defining the dentition impression 18 maybe trimmed away in order to reduce or eliminate subsequent contact ofthe heated impression material with sensitive gingival tissues. FIGS. 6and 7 depict the set patient dentition impression 18 with wax overlaymaterial 14 in place. FIG. 8 is similar to FIG. 7 but illustrates theformed patient dental impression 18 with the wax overlay material 14having been removed.

[0074]FIGS. 9 and 10 are alternative cross-sectional views of the tray10 of FIG. 6 depicting the use of different types of impressionmaterials. FIG. 9 depicts a patient dentition impression 18 formed froma conventional impression material, e.g., alginate. FIG. 10alternatively depicts an impression tray 10 and set patient dentitionimpression 22 formed from an impression material that includes aparticulate filler material. The particulate filler material is includedin order to increase the specific heat of the patient dentitionimpression 22 so that it is capable of absorbing and transferring agreater quantity of heat energy per unit of time.

[0075]FIG. 11 depicts the step of loading the patient dentitionimpression 18 (or 22) with a dental composition by means of a syringe20. An example of an appropriate bleaching composition is a 15%carbamide peroxide gel whitener or bleaching agent, optionally oralternatively with a fluoride and/or potassium nitrate additive. Becausethe act of placing the dental tray 10 into the patient's mouth willtypically cause the dental composition to spread out and coat the toothsurfaces, there is no specifically required method of loading thedentition impression 18 (or 22). In one embodiment, it may be desirableto coat the interior labial surfaces of the set patient dentitionimpression 18 (or 22) corresponding to the patient tooth surfaces to betreated with approximately 0.5 to 1 cc. of the dental composition. Thetray is then inserted into the patient's mouth in a manner so as atleast approximately register the formed patient dentition impression 18(or 22) with the patient's teeth to be treated.

[0076]FIG. 12 depicts the step of treating the patient's teeth. The tray10 and set patient dentition impression 18 (or 22) are typically heatedbefore or after insertion of the tray into the patient's mouth,depending on the type of heat source that is employed. In the case wherethe dental tray includes a heating means, such as a resistive heatingelement or a heated fluid, the tray is typically heated after insertioninto the patient's mouth, although it may optionally be preheated priorto insertion into the patient's mouth. On the other hand, in the casewhere the tray is heated using a completely external heat source, suchas a heater or microwave, the tray will typically be heated beforeinsertion into the patient's mouth, with stored heat providing thedesired energy for heating the dental composition.

[0077] Regardless of the method used to heat the formed dentitionimpression, the formed dentition impression and/or the dentalcomposition should be maintained at a temperature of at least about 105°F. in order to accelerate the activity of the active dental agent. Thedental composition and/or formed dentition impression are preferablyheated and maintained at a temperature in a range of about 110° F. toabout 150° F, more preferably in a range of about 120° F. to about 140°F., during treatment.

[0078] In addition, the dental tray will typically remain in thepatient's mouth for a period of time in a range of about 1 minute toabout 60 minutes, more preferably in a range of about 5 minutes to about30 minutes, depending on the dental treatment being performed, thestrength of the active dental agent, the operating temperature(s), andthe like. Although not a precise measurement, it has been found that,for every 10 degree increase in the operating temperature, the timeperiod for performing a particular dental treatment is cut approximatelyin half In the case where a tray is heated externally, such as by meansof microwave energy, it may be necessary to reheat the tray periodicallyas it cools off in the patient's mouth, optionally with the additionalstep of replenishing the dental composition.

[0079] IV. Compositions Used in Conjunction With the Inventive Apparatusand Methods.

[0080] In general, there are two different types or classes ofcompositions that will be used together with the inventive apparatus—animpression material used to form a dentition impression and a dentalcomposition used to carry out a desired dental treatment. The presentinvention contemplates the use of both conventional impression materialsand dental compositions, as well as impression materials and dentalcompositions that may be specially formulated for use in conjunctionwith the inventive apparatus.

[0081] A. Impression Materials.

[0082] Any plastic and deformable material known in the art that iscapable of making an impression of a person's teeth may be used incombination with the apparatus of the present invention. In order forthe dentition impression to be easily formed and then maintain its shapeonce formed, it will be preferable to use a material that can set orcure in a relatively short period of time, such as in a matter ofminutes or even seconds, after being placed into a patient's mouth.

[0083] Alginate impression materials are presently the preferredimpression material according to the invention. Alginate impressionmaterials are a common feature in most dental offices and are regularlyused to make impressions of a patient's teeth for a variety of reasons.Therefore, dentists are familiar with how alginates are mixed, utilizedand set to form a reliable and resilient dentition impression. Alginatematerials are also non-toxic and are set or cured by hydration withwater. They are relatively inexpensive and readily available. Becausethey are initially water soluble, a wide range of flavorants may be usedto enhance the taste and decrease the tendency of patients to gag whiletaking an impression.

[0084] Notwithstanding the foregoing, virtually any settable impressionmaterial may be used Examples of alternative impression materialsinclude silicone rubbers, polyethers, and epoxies.

[0085] In order to increase the heat capacity of dental impressionmaterials, particularly materials such as silicone, polyethers orepoxies that do not absorb or transfer heat as well as alginatematerials, it may be desirable to mix a heat-retention material into theimpression material, such as a particulate or fibrous filler. Examplesof suitable materials that may be used to increase the heat capacityand/or the heat transference properties of the impression materialsinclude metal fibers or powders, ceramic fibers or powders, or mineralfibers or powders.

[0086] By way of example, polished 2 mm.-3 mm. size, stone chips may beadded and uniformly mixed into an unset alginate dental impressioncomposition in the ratio of approximately 12½ parts by weight ofpolished dental stone chips to approximately 87½ parts by weight ofunset alginate dental impression material. Inclusion of the aggregate inthe composition extends the length of time during which the patientdental impression, following heating by microwave oven equipment orother heating means, will remain above the minimum temperature of about105° F. while being held in the patient's mouth.

[0087] On the other hand, the heat transferability qualities ofimpression materials such as silicone and polyethers, which do notreadily transfer heat, may be increased through the use of moreconductive fillers such as those based on metals or more conductiveceramics materials.

[0088] B. Dental Compositions.

[0089] It is within the scope of the invention to utilize any dentalcomposition that may be found to have increased activity or reducedtreatment time when subjected to heat. Examples include dental bleachingcompositions, desensitizing compositions, and remineralizingcompositions. Dental bleaching compositions are characterized by theinclusion of a dental bleaching agent, e.g., carbamide peroxide, aqueoushydrogen peroxide, sodium perborate, and the like. Desensitizingcompositions are characterized by the inclusion of a desensitizingagent, e.g., potassium nitrate, other potassium nitrate salts likepotassium citrate, citric acid, citric acid salts, strontium chloride,fluoride salts, and the like. Remineralizing compounds are characterizedas including a fluoride salt such as sodium fluoride, stannous fluoride,sodium monofluorophosphate, and the like.

[0090] It will be readily understood that the dental compositionsaccording to the present invention may include a plurality of activeagents, such as two or more of a bleaching agent, a desensitizing agent,a remineralizing agent, or some other active dental agent (whether ornot activated by heat so long as the composition includes at least oneactive agent that is activated by heat).

[0091] It is within the scope of the invention to use both conventionalbleaching compositions known in the art as well as bleachingcompositions that may be specially formulated to take advantage of theheat-induced bleaching activity described herein. In general, dentalbleaching compositions that include relatively high concentrations ofbleaching agent (e.g., 35%) and are highly stable for good shelf lifeare well-suited for use in the present invention. Nevertheless, it iscertainly within the scope of the invention to use two-part systems thatbecome destabilized upon mixing the parts, or even bleachingcompositions having lower concentrations of bleaching agent (e.g.,5-10%).

[0092] A wide range of dental bleaching compositions are available fromUltradent Products, Inc., located in South Jordan, Utah, under thegeneral name of Opalecence®. Opalecence® products sold and distributedto patients for in-home use are available in various strengths measuredby the concentration of the bleaching agent, which, in the case ofpresently formulated at-home bleaching compositions, is carbamideperoxide. In particular, Opalecence® formulated for home-use isavailable in concentrations of 10%, 15% and 20% by weight carbamideperoxide. Opalecence® Quick, which is specially formulated fornon-dentist supervised bleaching on site in a dental office waitingarea, includes 35% by weight carbamide peroxide. Opalecence® Extra,which is specially formulated for dentist supervised in-officebleaching, contains 35% by weight of hydrogen peroxide together with alight-absorbing component for absorbing light from a radiant energysource, such as a dental curing light or a laser.

[0093] Compositions and methods for manufacturing a wide range of dentalbleaching compositions, such as those exemplified by Opalecence® brandbleaching compositions, are generally described in U.S. Pat. No.5,376,006. Compositions and methods for manufacturing a wide range ofdental bleaching compositions that include higher concentrations ofbleaching agent, are generally described in U.S. Pat. No. 5,858,332.Compositions and methods for manufacturing a wide range of dentalbleaching compositions that include a light-absorbing component andoptionally higher concentrations of bleaching agent, are generallydisclosed in U.S. Pat. No. 5,785,527. For purposes of disclosing dentalbleaching compositions suitable for use in conjunction with theapparatus, methods and kits of the present invention, the foregoingpatents are incorporated herein by reference.

[0094] Ultradent Products, Inc. also sells a desensitizing compositionunder the name of UltraEZ®, which includes 3% by weight potassiumnitrate and 0.11% by weight fluoride ion within a sticky, viscous gelformulation. A duel desensitizing/remineralizing composition thatincludes 1.1% by weight sodium fluoride is sold under the name ofFlor-Opal®. In addition, a variety of blended compositions that includevarious concentrations of carbamide peroxide (10%, 15% or 20%), togetherwith 3% potassium nitrate and 0.11% fluoride ion, are sold under thename of Opalecence® PF. Finally, blended compositions that includevarious concentrations of carbamide peroxide (15% or 20%), together with0.11% fluoride, are available under the name of Opalecence® F.

[0095] Compositions and methods for manufacturing a wide range ofdesensitizing compositions, such as those exemplified by UltraEZ®, orblended bleaching compositions such as Opalecence® PF, are generallydescribed in U.S. Pat. No. 5,855,870 and U.S. Pat. No. 5,851,512.Compositions and methods for manufacturing remineralizing compositionsthat include a fluoride salt are generally described in U.S. Pat. No.5,376,006. For purposes of disclosing dental compositions suitable foruse in conjunction with the apparatus, methods and kits of the presentinvention, the foregoing patents are incorporated herein by reference.

[0096] V. Kits.

[0097] It is within the scope of the invention to sell, or otherwiseprovide, one or more of the foregoing apparatus and compositions in theform of a kit. For example, a kit may advantageously include a dentalimpression tray and one or more dental compositions. In a preferredembodiment, a kit may advantageously include a dental impression trayhaving means for heating a formed patient dentition impression, such asa resistive heating element, and one or more of a dental bleachingcomposition, a desensitizing composition, a remineralizing composition,or a blended composition that includes more than one active dentalagent. The kit may include multiple dental impression trays togetherwith multiple doses of one or more dental compositions. For simplicityof storage and delivery, the dental compositions may advantageously beloaded into and delivered from a syringe, such as a syringe thatincludes a unit dose of the dental composition.

[0098] Although the kit may also include an impression material, thismay not be necessary in many cases in view of the fact that manydentists typically keep ample alginate impression material on hand totake dental impressions for a variety of different reasons. Virtuallyany material capable of taking a dentition impression may be used withinthe kits of the present invention. Alginate impression materials arepresently preferred due to their low cost, ready availability and easeand familiarity of use.

[0099] A particulate or fibrous filler for increasing the heat capacityand/or heat transferability may be included within the kits, eitheralone, in combination with but separate from an impression material, orpremixed within an impression material.

[0100] The kits may also include a suitable power supply designed toprovide a desired amount or range of power in order to heat and maintainthe dental impression tray and accompanying impression material at adesired temperature or within a desired temperature range. In the casewhere the impression trays are disposable, i.e., are to be used and thendisposed of after each use, it will generally only be necessary topurchase one power supply (or optionally one power supply per dentalchair in the case of multiple-chair offices) that may be used with aseries of trays purchased at the same time as the power supply orthereafter.

[0101] The kits may include one or more wax overlay sheets in order toact as a blockout material on the surface of the patient's teeth (seeFIG. 2). Alternatively, the blockout may be an amorphous material thatcan be brushed, sprayed or other pressed onto the tooth surfaces. Theterm “amorphous blockout material” shall broadly include any materialother than a sheet that can be applied to a person's teeth in order totemporarily increase the apparent thickness of the teeth duringformation of the patient dentition impression. One purpose for doingthis is to increase the size of the dentition impression, particularlyat the interface between the impression material and the labial toothsurfaces to be treated, in order to create a reservoir for the inclusionof additional dental composition during treatment.

[0102] VI. Summary.

[0103] The invention provides apparatus and methods for use inaccelerating the bleaching activity of conventional bleachingcompositions in a manner that is both more comfortable from the point ofview of the patient and more economical in terms of cost and time.

[0104] The invention further provides apparatus that is disposable andthat is of sufficiently low cost and simplicity of design so that it canbe used for a single patient and then disposed of.

[0105] The invention also provides apparatus and methods that can beused to accelerate the activity of other dental compositions, such asdesensitizing and/or remineralizing compounds that include, e.g., apotassium nitrate and/or fluoride salt.

[0106] The present invention may be embodied in other specific formswithout departing from its spirit or essential characteristics. Thedescribed embodiments are to be considered in all respects only asillustrative and not restrictive. The scope of the invention is,therefore, indicated by the appended claims rather than by the foregoingdescription. All changes which come within the meaning and range ofequivalency of the claims are to be embraced within their scope.

What is claimed and desired to be secured by United States LettersPatent is:
 1. A method of treating a person's teeth comprising:providing a dental impression tray having means for receiving a dentalimpression material used in making an impression of at least a portionof a person's teeth and means for heating the dental impression materialreceived by the dental impression tray; placing a dental impressionmaterial at least partially within the dental impression tray; insertingthe impression tray and impression material into a person's mouth so asto form an impression within the impression material of the person'steeth; removing the impression tray with the formed impression from theperson's mouth; placing a dental composition suitable for a desiredtreatment into the formed impression of the person's teeth; insertingthe impression tray containing the dental composition within the formedimpression into the person's mouth; and heating the dental compositionto a temperature of at least about 105° F. while maintaining theimpression tray within the person's mouth for a desired treatmentinterval.
 2. A method of treating a person's teeth as defined in claim 1, wherein the dental impression tray includes a generally arcuatestructure defining an interior region configured to receive the dentalimpression material, a handle attached to the arcuate structure, aresistive heating element disposed at least partially within or adjacentto the interior region, and electrical wires in electrical communicationwith the resistive heating element for transmitting an electric currentto the heating element.
 3. A method of treating a person's teeth asdefined in claim 2 , wherein the arcuate structure includes an interiorsurface oriented so as to be approximately parallel to a person's toothsurfaces when the dental impression tray is positioned within theperson's mouth, wherein the impression tray further includes asubstantially planar barrier orthogonal to the interior surface of thearcuate structure and oriented so as to receive impression material onat least one surface of the barrier.
 4. A method of treating a person'steeth as defined in claim 2 , wherein said arcuate structure has anapproximately U-shaped cross section defining an interior cavity forreceipt of dental impression material.
 5. A method of treating aperson's teeth as defined in claim 1 , wherein the dental compositionincludes a dental bleaching agent in an amount sufficient to effectbleaching of a person's teeth.
 6. A method of treating a person's teethas defined in claim 5 , wherein the dental bleaching agent includes atleast one of carbamide peroxide, hydrogen peroxide, or sodium perborate.7. A method of treating a person's teeth as defined in claim 1 , whereinthe dental composition includes a desensitizing agent in an amountsufficient to reduce sensitivity of a person's teeth.
 8. A method oftreating a person's teeth as defined in claim 7 , wherein thedesensitizing agent includes potassium nitrate.
 9. A method of treatinga person's teeth as defined in claim 1 , wherein the dental compositionincludes a fluoride salt.
 10. A method of treating a person's teeth asdefined in claim 1 , wherein the dental composition is placed into theformed impression using a syringe.
 11. A method of treating a person'steeth as defined in claim 1 , wherein the person whose teeth are beingbleached assists in controlling the temperature of the dentalcomposition.
 12. A method of treating a person's teeth as defined inclaim 1 , wherein the dental composition is maintained at a temperaturein a range of about 110° F. to about 150° for a period of time in rangeof about 5 minutes to about 60 minutes while the impression tray iswithin the person's mouth.
 13. A method of treating a person's teeth asdefined in claim 1 , wherein the dental composition is maintained at atemperature in a range of about 120° F. to about 140° for a period oftime in range of about 5 minutes to about 60 minutes while theimpression tray is within the person's mouth.
 14. A method of treating aperson's teeth as defined in claim 1 , wherein the dental impressionmaterial placed at least partially within the dental impression tray isa curable impression material, the method further including the step ofallowing or causing the curable impression material to become at leastpartially cured prior to removing the impression tray with the formedimpression from the person's mouth.
 15. A method of treating a person'steeth as defined in claim 14 , wherein the curable impression materialis selected from the group consisting of filled or unfilled alginate,silicone, polyether, epoxy, and mixtures thereof.
 16. A method oftreating a person's teeth as defined in claim 1 , further including thestep of applying a blockout material to the person's teeth prior tomaking an impression so as to increase the size of the formed impressionso as to hold an additional quantity of the dental composition withinthe formed impression.
 17. A method of treating a person's teeth asdefined in claim 1 , further including the step of trimming and removinga portion of the impression material adjacent to the formed impressionso as to reduce the tendency of the impression material to contact theperson's gums during the heating step.
 18. A method of treating aperson's teeth comprising: one or more steps for obtaining an impressionformed within an impression material of a person's teeth to be treated;one or more steps for contacting the person's teeth with a dentalcomposition placed within the formed impression of the person's teeth;and one or more steps for heating the dental composition in contact withthe person's teeth to a temperature of at least about 105° F.
 19. Amethod of treating a person's teeth as defined in claim 18 , wherein theimpression material is a curable material selected from the groupconsisting of alginate, silicone, polyether, epoxy, and mixturesthereof, and optionally including a filler that increases at least oneof the heat capacity or heat transference of the impression material.20. A method of treating a person's teeth as defined in claim 18 ,wherein the dental composition includes at least one of a dentalbleaching agent, a desensitizing agent or a remineralizing agent.
 21. Amethod of treating a person's teeth comprising: providing a dentalimpression tray including a generally arcuate structure defining aninterior region configured to receive a dental impression material, ahandle attached to said arcuate structure, a resistive heating elementdisposed at least partially within or adjacent to said interior region,and electrical wires in electrical communication with said resistiveheating element for transmitting an electric current to said heatingelement; placing a curable dental impression material at least partiallywithin the dental impression tray, inserting the impression tray andcurable impression material into a person's mouth so as to form animpression within the impression material of the person's teeth;allowing or causing the curable impression material to become at leastpartially cured so as to yield a formed impression; removing theimpression tray with the formed impression from the person's mouth;placing a dental composition into the formed impression of the person'steeth, the dental composition including at least one of a dentalbleaching agent, a desensitizing agent or a remineralizing agent;inserting the impression tray containing the dental composition withinthe formed impression into the person's mouth; and heating the dentalcomposition to a temperature in a range of about 110° F. to about 150°F. while maintaining the impression tray within the person's mouth for adesired treatment interval.
 22. A method of treating a person's teeth asdefined in claim 21 , wherein the dental composition is heated to atemperature in a range of about 120° F. to about 140° F. during thedesired treatment interval.
 23. A method of treating a person's teeth asdefined in claim 21 , wherein the treatment interval is in a range ofabout 5 minutes to about 30 minutes.
 24. An apparatus for use intreating a patient's teeth comprising: a generally arcuate structuredefining an interior region configured to receive a dental impressionmaterial; a resistive heating element disposed at least partially withinor adjacent to said interior region; and electrical wires in electricalcommunication with said resistive heating element for transmitting anelectric current to said heating element.
 25. An apparatus as defined inclaim 24 , further including a handle attached to said arcuatestructure.
 26. An apparatus as defined in claim 24 , further including adental impression material disposed at least partially within saidinterior region.
 27. An apparatus as defined in claim 26 , wherein saiddental impression material comprises at least one curable dentalimpression material selected from the group consisting of alginates,silicones, polyethers, and epoxies.
 28. An apparatus as defined in claim24 , wherein the resistive heating element includes at least one of aresistive wire, an etched resistive circuit, or a metallic strip.
 29. Anapparatus as defined in claim 24 , wherein said arcuate structureincludes an interior surface oriented so as to be approximately parallelto a person's tooth surfaces when the dental impression tray ispositioned within the person's mouth, wherein the impression trayfurther includes a substantially planar barrier orthogonal to saidinterior surface of the arcuate structure and oriented so as to receiveimpression material on at least one surface of said barrier.
 30. Anapparatus as defined in claim 29 , wherein said barrier bisects theinterior region defined by said arcuate structure in a manner so as tocreate an upper interior region oriented so as to receive impressionmaterial for making an impression of at least a portion of a person'supper teeth and a lower interior region oriented so as to receiveimpression material for making an impression of at least a portion of aperson's lower teeth.
 31. An apparatus as defined in claim 24 , whereinsaid arcuate structure has an approximate U-shaped cross sectiondefining an interior cavity for receipt of dental impression material.32. An apparatus as defined in claim 24 , further including a powersupply means for providing an electric current to the heating means soas to heat and maintain a dental impression material disposed at leastpartially within said impression tray to a temperature of at least 105°F.
 33. An apparatus as defined in claim 32 , wherein said power supplymeans includes a temperature control device operable by a person whoseteeth are being treated.
 34. An apparatus as defined in claim 32 ,wherein said power supply means regulates the temperature of the dentalimpression material by means of a diode associated with said dentalimpression tray.